THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

ZORAIDA SAMBOLIN, CNN ANCHOR: Breaking news: explosions and flames too difficult to fight. A fire burning out of control in a pair of field barges close to a cruise ship.

JOHN BERMAN, CNN ANCHOR: New clues in the investigation into the Boston marathon bombings. We now know what may have been used to trigger the deadly blasts.

Plus, tracking down the Russian connection. CNN with a first-hand look at the place where the suspects may have learned to make their bombs.

Good morning, everyone. Welcome to EARLY START. I'm John Berman in Boston.

We will have live coverage from here coming up in just a few minutes.

SAMBOLIN: And I'm Zoraida Sambolin, in New York. It is Thursday, April 25, 5:00 a.m. in the East.

ANNOUNCER: This is CNN breaking news.

SAMBOLIN: We begin with breaking news overnight.

Two fuel barges burning at this hour. They're docked in Mobile, Alabama. The fires are simply too hot and too dangerous for firefighters to battle there. The barges are loaded with gasoline. They exploded. Take a look at that. This was last night.

Officials say there were at least six explosions. They were heard up to 20 miles away. The shipping channel where the barges are docked are closed right now and leaves three people hospitalized. We do not know what condition they're in. Fire officials believe everyone has been accounted for.

The barges are burning not far from where the crippled Carnival Triumph is docked. It was towed into port in February after an engine fire left it adrift at sea with more than 4,000 people on board. We're going to continue to follow this developing story for you.

In the meantime, let's head back to Boston. John Berman is standing by there.

BERMAN: Thanks, Zoraida. Important new developments to tell you about in the Boston marathon bombing case. Right now, the Tsarnaev brothers apparently used a remote control device similar to one used to operate a toy car to set off those explosive devices. That could be a critical piece of information for investigators.

Plus, we're told the father of the suspected bombers Anzor Tsarnaev is set to fly to the U.S. as early as tomorrow. He is said to be cooperating with the FBI.

We're also finding out the Russians not only warned the FBI about Tamerlan Tsarnaev, they also asked the CIA to investigate him but both agencies determined there was not enough hard evidence to act on. A lot of questions about that.

We begin our coverage this morning with CNN's Miguel Marquez right here in Boston.

We begin at the beginning where this bomb blew up. This is the finish line of the Boston marathon and over here in front of marathon place sports is where the first bomb exploded. It now is hallowed ground.

(BEGIN VIDEOTAPE)

MARQUEZ (voice-over): Investigators tell CNN and other news agencies at least one of the homemade bombs was triggered by remote control, possibly a crucial clue. Were the devices based on a blueprint in al Qaeda's English language magazine "Inspire" or similar to ones built in camps run by Dagestani militant Abu Dujan? Whether he or Tamerlan Tsarnaev ever met now one part of this massive worldwide investigation.

("TAPS" PLAYS)

MARQUEZ: This as Boston's dead are remembered.

ROBERT ROGERS, SEAN COLLIER'S BROTHER: He was born to be a police officer and he lived out his dreams.

MARQUEZ: Thousands in attendance for a memorial for MIT police officer Sean Collier.

ROGERS: Officer Sean Collier, we love you.

MARQUEZ: In attendance, Vice President Biden who seemed to make news by suggesting the Tsarnaev brothers were self radicalized.

JOSEPH BIDEN, VICE PRESIDENT OF THE UNITED STATES: Why? Whether it's al Qaeda central out of the Fatah, or two twisted, perverted, cowardly, knock-off jihadis?

ANNA BURSAUS, BOSTON PRESIDENT: I think for life in Boston, it's very important that things move on because everyone's been very much -- very upset for the past week.

MARQUEZ: The urban flow returning to Boylston Street, except at the location of each bombing.

Those places, like a world still on hold. Those places of reflection, places where emotions still flow.

And at the memorial to the victims, Jill Biden, wife of the vice president, stopped to pay her respects.

(END VIDEOTAPE)

MARQUEZ: Now, 33 victims still remain in area hospitals here, one in critical condition. And for the remaining bomber, Dzhokhar Tsarnaev, he may be moved from Beth Israel in the next couple of days -- John.

BERMAN: Thanks so much, Miguel.

Where Miguel is standing, there is such a mixture of emotions between tragedy and jubilance. I mean, people were on the street packed there yesterday, Miguel, where you are standing there. But as you said, such emotional scene where the bombs went off and also the memorials.

Miguel, our thanks to you.

MARQUEZ: Yes.

BERMAN: The Tsarnaev brothers were apparently -- the Tsarnaev brothers were apparently planning a trip to New York City following the bombings. New York's police commissioner says investigators learned of those plans from surviving suspect Dzhokhar Tsarnaev. But there is no evidence that the brothers were plotting an attack. The commissioner says they planned to party in the Big Apple.

We're also learning what could be a critical piece of the puzzle here: a small scale militant in Dagestan ran bomb-making training camps for foreign visitors. Russian special forces killed Abu Dujan in December. And as CNN reported, Tamerlan Tsarnaev had a video of Abu Dujan on his YouTube channel. But we don't know for sure if the two men ever met face-to-face during Tamerlan's visit to Russia.

Nick Paton Walsh is following the developments from the capital of Dagestan.

(BEGIN VIDEOTAPE)

NICK PATON WALSH, CNN INTERNATIONAL CORRESPONDENT (voice-over): This is Dagestani militant Abu Dujan in a video one of the alleged Boston bombers Tamerlan Tsarnaev posted on his YouTube Channel. Russian special forces killed Abu Dujan in a shootout last December in Dagestan and we don't know if he ever met Tsarnaev. But Dagestani police have revealed to CNN the small time militants ran training camps for bomb-making that foreigners came to. Police gave us images of Abu Dujan's group training in the woods.

This one explains how to mix and prepare home-made explosives almost anywhere. And the group's pictures suggest they learned to use a mobile phone as a detonator.

The local police chief who helped hunt him down Abu Dujan says the militant trained foreigners.

ASKHABALI SAUERBEKOV, POLICE CHIEF, KIZIL YURT (through translator): We do not have audio or visual confirmation but we do have information confirming that Abu Dujan met with foreigners.

WALSH (on camera): What did the foreigners learn in the woods?

SAUERBEKOV: I can't talk about the number of foreigners but they met to exchange their bandit experience. They are Dagestanis who have taken citizenship elsewhere and come here to meet in the historical motherland whose roots are here.

WALSH (voice-over): And could that have included Americans?

SAUERBEKOV: It's entirely possible but I know there were Arabs and Turks among them. But whether there were Americans, I don't know.

WALSH (on camera): The police chief told us that Abu Dujan was often observed coming here to the heart of Makhachkala, to this Salifist Islamic mosque behind me which itself denies any links to extremism. It is possible, though, that Tamerlan Tsarnaev last year also prayed here.

SAUERBEKOV: Of course, the (INAUDIBLE) mosque is their mosque, where all the Wahhabists go. Our technological work gives us operational information that Abu Dujan went there, met people, and agitated. Not once but many times.

WALSH: There are reports that Dujan was observed at the mosque and he was observed meeting Tsarnaev. Do you know this?

SAUERBEKOV: I really can't answer this. For different reasons, I can't answer. You understand me?

(END VIDEOTAPE)

WALSH: That doesn't mean that Tamerlan Tsarnaev and Abu Dujan ever met. But if you look at the jigsaw here, there seem to be pieces almost overlapping in many ways, and if it were that the elder alleged Boston bomber wanted some sort of bomb-training, it's entirely possible he could have gotten it from Abu Dujan here.

I should add now that we have just finished an interview with the mother of the alleged Boston bombers, Zubeidat Tsarnaev. She spoke to us at length for about half hour on many aspects of this case. One interesting thing stood out. She said the FBI did come to them in 2011 because they had become concerned, what they referred to is the radical elements of the elder brother Tamerlan Tsarnaev's fate. They said they were going to be watching him and watching people like him just in case they turned into some sort of extremists or had the capacity towards violence.

That's them taking a point they deny that he had any intention to do that at all and describe how he at some point in the 2000s when he was in America turned to the Islamic faith and, fact, Tamerlan telling his mother to put on a head scarf because that's how Islamic women should properly behave according to their mores.

She also went on to say how she believes that police took her son alive. She's seen video of a naked man being bundled into a police car during the manhunt. She believes that actually was Tamerlan. I think that gives you an idea really of the level of justification she is trying to find herself, to reconcile her two different beliefs, that her sons did not commit this crime and while seeing all this photographic evidence from U.S. officials that might suggest that they did. A woman who's clearly distraught in many different ways -- John.

BERMAN: An interesting combination of information there and also conspiracy theories.

Nick Paton Walsh in Dagestan for us this morning, thanks so much, Nick, for that really interesting piece of the puzzle.

Let's go back to Zoraida back in New York.

Hey, Z.

SAMBOLIN: Thank you very much, John.

It's 10 minutes past the hour.

And happening now, picking up the pieces. The National Weather Service confirming two tornadoes struck the New Orleans area yesterday. It damaged several homes. They were part of a series of powerful and intense storms that battered that region, flooding streets, knocking out power to some 30,000 customers in southeast Louisiana.

Jennifer Delgado is monitoring the situation for us as well, as the continuing flooding in the Midwest. I was asking earlier, this is the worst flooding they've seen, because folks that are in and around the Chicago land area are saying they have never seen anything like this.

JENNIFER DELGADO, AMS METEOROLOGIST: You know what? We've seen flooding across parts of Missouri as well as Illinois, a lot worse than years in the past. But I want to show you what we're looking at now. Some of the reports from the tornado from yesterday out of New Orleans, we do know it was an EF-1, as well as an EF-0. And here it is. You can kind of see where it moved through Jefferson Parish yesterday. Now, the good news is, all that severe weather is gone. What we're looking at some rain showers, trying to make its way off the East Coast. You can see for New York and Boston, very light scattered showers there. And the same for parts of the Midwest, mainly looking at showers. You can see the Upper Peninsula, we're looking at a little bit of snow.

But, again that, is now going to amount too much, and that's good news because many of these areas, as Zoraida said, still dealing with some awful flooding. Certainly, Chicago, this is one of the worst you've seen in many, many years.

I want to point out to you for the Des Plaines, we're talking minor flooding there. But for areas like Cape Girardeau right long the Mississippi River, moderate flooding. We're expecting that to crest at major flood stage tomorrow and then it will continue to fall down. We're talking receding.

And as we go through the next couple of days. It will be a little slow. But the area that we're watching for potential flooding, that's going to be in the Northern Plains across parts of the Dakotas. We're talking cold temperatures right now.

We have a big warm-up on the way. Temperatures are going to be running 15 degrees above average. That is going to spell rapid snow melt. And that is going to lead to flooding for areas like Fargo as we go through the next couple days. You can see the temperatures are going to soar. This is warmest they've seen whole year.

On wider view across parts of the U.S., temperatures are still going to be a little cool across the Midwest, that includes Chicago where today they're expecting high of 57 degrees and 70s towards the South.

So, certainly, that flooding has been a mess. And we'll continue to follow the area up North.

SAMBOLIN: Yes, that cleanup is the next mess, and the folks that are expecting it.

Jennifer Delgado, thank you very much.

DELGADO: You're welcome.

SAMBOLIN: Twelve minutes past the hour.

Five living U.S. presidents will be on hand later this morning for the dedication of the George W. Bush Presidential Library in Dallas. The nation's 43rd president is currently enjoying being a new grandfather. He has become somewhat obsessed with painting, we understand.

He says the new library is all about laying out the facts and he tells our John King he doesn't feel any need to defend himself or his presidency.

(BEGIN VIDEO CLIP) GEORGE W. BUSH, FORMER U.S. PRESIDENT: I know this. Laura and I gave the presidency eight years of our life. We gave it our all. We made the best judgment calls I could. Didn't compromise my principles. And I'm a content man.

(END VIDEO CLIP)

SAMBOLIN: Well, it appears the nation is beginning to look a little more kindly on the Bush presidency. According to a new CNN/ORC poll, 68 percent of Americans considered his two terms in office a failure right after he left the White House. That was early 2009. Now, that number has fallen to 55 percent.

And stay with CNN all morning. In the 8:00 hour of "STARTING POINT," former First Lady Laura Bush takes our John King on a tour of new Bush presidential library. Looking forward to that.

And new information in the case of the letters tainted with ricin. Why the FBI is now focusing on a former politician and a martial arts studio.

EARLY START back after this.

(COMMERCIAL BREAK)

BERMAN: Welcome back, everyone. I'm John Berman, live in Boston.

Here are the latest developments in the marathon bombing investigation.

The father of Tamerlan and Dzhokhar Tsarnaev is cooperating with the FBI. He will fly to the United States tomorrow for questioning.

And we've learned that the suspected bomber used a remote control for a toy car to detonate the explosives at the marathon finish line.

Also this morning, we're learning the Russians not only warned the FBI about Tamerlan Tsarnaev. They also asked the CIA to check him out, but neither agency believed there was enough hard information to act on.

Meanwhile, Zoraida, back here in Boston, Boylston Street behind me opened yesterday, packed. Crowds of people walking on the streets going to the restaurants. The mayor actually has said there will be free parking on Boylston Street until this weekend because he wants people back here, you know, to go to all the businesses and buy as much up as they can.

SAMBOLIN: That's a great idea. I suspect you'll be having lunch and dinner there as well, John.

BERMAN: Do what I can.

SAMBOLIN: All right. Thank you.

Eighteen minutes past the hour. We're monitoring breaking news this morning: two fuel barges burning at this hour docked in Mobile Bay, Alabama. Take a look at that. The fires so hot, so dangerous. Firefighters cannot battle it. The barges loaded with gasoline exploded last night. At least six explosions were reported. They were heard up to 20 miles away.

The shipping channel is closed. At least three people were hurt. We don't know their conditions at this hour. Fire officials believe everyone has been accounted for there.

We're going to continue to monitor the developments.

And we're following new developments in the investigation of the ricin-tainted letters sent to President Obama and others on Capitol Hill. The FBI's focus now has shifted. They're now searching the site of a formal martial arts studio in Tupelo, Mississippi, and the home of a former politician who was an instructor there.

Victor Blackwell is monitoring all of these developments for us.

Victor, any idea if investigators found anything?

VICTOR BLACKWELL, CNN CORRESPONDENT: Zoraida, no. No reports from the FBI today that they found anything. But I'll tell what you we're finding is that this unusual story is become even more bizarre shifting from a celebrity impersonating political activist to a taekwondo-teaching insurance professional who once ran for public office.

(BEGIN VIDEOTAPE)

BLACKWELL (voice-over): The home of a former Republican candidate for the Mississippi statehouse is involved in a federal investigation into who sent letters tainted with ricin to President Obama, a Mississippi senator and a county judge.

Federal agents in full body hazmat suits searched his home on Tuesday. His attorney said it was related to the ricin investigation.

In a YouTube video posted this week, the former candidate J. Everett Dutschke talked about the search.

J. EVERETT DUTSCHKE, FORMER POLITICIAN AND MARTIAL ARTS INSTRUCTOR: I met with the FBI. I consented to a paper saying go ahead and search the house.

BLACKWELL: On Wednesday, agents spent several hours searching a taekwondo studio he Dutschke had rented until January. It's not known if anything was found. The studio shut down after Dutschke was arrested on child molestation charges. His attorney says he is now free on bond.

The FBI has not filed any new charges in the ricin investigation and Dutschke has not been named as a suspect. The charges against the celebrity impersonator Kevin Curtis have been dropped. DUTSCHKE: During Kevin Curtis, the ricin mailer, during his pretrial hearing, his attorney accused me of being the one that sent out the ricin letters instead of him.

BLACKWELL: His attorney told CNN Dutschke had nothing to do with the letters. But earlier, Curtis told CNN he still believes he'd been set up.

KEVIN CURTIS, IMPERSONATOR: I knew it had to be or they had the wrong person.

DUTSCHKE: I don't have anything at all to do with this. I don't hardly know the guy. In fact, we've only met on two occasions.

BLACKWELL: Curtis said he had bad mouthed him for years and is now implicating him in a plot to poison the president.

CURTIS: That's serious. That's when someone says, we want him gone.

(END VIDEOTAPE)

BLACKWELL: We had a conversation with Dutschke's attorney, Laurie Basherman (ph). She was there was one other search that was a BOLO. Be on alert for one of the vehicles that were owned by the Dutschkes. We were told once that information came out that Everett Dutschke drove that car to the FBI, it was processed. She's not aware if that car has been returned to him -- Zoraida.

SAMBOLIN: And coming up next, some good news for the economy. K.S. to prom season? Oh, OK, I'm like, what is that all about? Apparently, it's thanks to prom season.

EARLY START after this.

(COMMERCIAL BREAK)

SAMBOLIN: Welcome back. Twenty-five minutes past the hour.

Christine Romans is here. We are minding your business this morning.

CHRISTINE ROMANS, CNN BUSINESS CORRESPONDENT: Good morning.

Future is higher this morning. We're watching those. The big headlines are overseas this morning, Zoraida. The U.K. economy grew ever so slightly in the first quarter, up just 0.3 percent. So that means no triple dip recession for the U.K.

In Spain, the jobless rate, look at this number. It hit a new high this morning, 27.1 percent. Compare that to the 17 countries in the eurozone, 12 percent unemployment.

All right. So how is this for a quirky economic forecast in the U.S.? Let's call it the prom indicator. For the second year in a row, families are spending more on prom.

Visa says the average U.S. household spends $1,139 on prom-related events. That's up 5 percent from last year. Families in the Northeast spend the most on average, more than $1,500. Families in the Midwest, spend the least, around $720.

Parents pay 59 percent of the costs, Visa says. Kids kick in 41 percent. You know, research says as long as mom and dad are paying more, teens have incentive to cut their costs. One troubling statistic in this survey, families who make less than $50,000 are planning to spend more than the national average -- which surprised me.

SAMBOLIN: You probably appreciate though the fact that the kids are paying anything at all, right? You think they should pay 50 percent.

ROMANS: I was surprised they pay that much, 41 percent. But, you know, they really go all out. When I was growing up, I didn't have a limo. I didn't have any of that kind of stuff. No hotel rooms to get ready, no stylist, no hair people.

SAMBOLIN: They do all that these days?

ROMANS: That's what they have. They pay $1,100.

SAMBOLIN: Prepare yourselves.

All right. Thank you, Christine.

ROMANS: You're welcome.

SAMBOLIN: Twenty-seven minutes past the hour.

If you're just waking up, evacuations overnight near the scene of explosions. Take a look at them. That's on the water on the Gulf of Mexico. Breaking news coverage, coming up.